Current interrupting switch having a movable contact carried by a magnetic armature



Aprll 21, 1964- DOUCHET 3,130,278

CURRENT INTERRUPTING SWITCH HAVING A MOVABLE CONTACT CARRIED BY A MAGNETIC ARMATURE Filed Dec. 7, 1960 IIIIIIIHHHHIH INVENTOR. FLOP/MGA/D DOUGH/FT ATfOPNEVJ MM 54mm 9% United States Patent O CURRENT INTERRUPTING SWITCH HAVING A MOVABLE CONTACT CARRIED BY A MAG- NETIC ARMATURE I g Flor-intend Douchet, 41 Rue Henri Vasseur, Argenteuil, France, assignor of one-half to Vehicules 'et Travaux,

VETRA, Paris, France, a French company Filed Dec. 7, 1966, Ser. No. 74,283 Claims priority, application France Dec. 14, 1959 6 Claims. (Cl. 2il(l19) It is known to efiect the immobilization of both contact-studs of a current switch by making use of the force of attraction acting between a permanent magnet and an armature of magnetic metal.

It is also known that it is an advantage to efiect the separation of the contact-studs at the highest speed which is compatible with the mode of construction of the apparatus.

It is again also known to blow-out the'electric are pro duced when the current is broken, by striking said are in a suitably orientated magnetic field.

Whatever precautions may be taken during the manufacture of the apparatus, it has been noted as a result of experience that, on accountof the existence of said breaking arc, the contacts or contact-studs become dirty and eroded after a certain length of service.' Such soiled and eroded conditions endanger the proper working of the apparatus, necessitate overhauls and possibly the replacementof the contact-studs." These operations themselves require troublesome interruptions of the service provided by the apparatus. 7 'The present invention has for itsparticular object to reduce as much as possible the frequency of overhauls orinsp'ections and the frequency of replacement of the contact-studs.

A further object of the invention is to provide very easy access to the contact-studs, in such manner as to reduce to a substantial extent the time of immobilization made necessary by such inspections or replacements.

The present invention is especially, although not ex- 3,130,278 Patented Apr. 21, 1964 a metallic block 4 provided with a housing 3 in which a detachable unit illustrated separately in FIG. 3 is intended to be pivotally mounted, a permanent magnet 19 serving tohold the said unit in the position of closure of the contact,'a permanent magnet 20 creating a magnetic field in the zone in which the breaking electric arc is produced and finally, a fixed contact-stud 18.

The detachable unit mentioned above comprises a strip 9 in which a hole 5 is pierced at one of the extremities thereof; a stud 6 is passed through said hole, and when said unit is mounted in position in the apparatus, said hole constitutes an articulation permitting of a slight oscillation of the strip 9 with respect to the block 4. A spring-blade 8 and a bearing member 2, suitably spaced at a distance apart from the strip 9 by means of an inter calary member7, are rigidly attached to the said strip. In addition a stirrup member 10 fitted with a roller 11 is also fixed to the strip, thereby permitting slight movements of oscillation to be imparted to said strip about the articulation 65. In the position of operation, the said movement is produced by the co-operation of the roller 11 with a circular cam 12 on which is formed a clusively, applicable to the material employed in electric traction for transportation'both by rail and road, for which the reduction of periods of immobilization is a factor of great importance.

In order to achieve the aims referred-to above, a switch in accordance with the invention is chiefly characterized in that the movable stud of the contact is rigidly fixed to a detachable part which is designed. to be easily separated from the main body of the apparatus.

In a preferable formof embodiment of the invention,

" hollow portionof the'cani 12.

the mechanical coupling between the movable stud and '5 the detachable part is formed by a light-weight elastic strip which is normally caused to be deformed when the two studs are in contact with each other.

The present invention therefore also has for its object,

by way of new industrial products, those switches com prisingthe combination of the characteristics explained above. g p Q g 1 Further characteristic features of the invention will be brought out by the description which follows below, refershoulder 21. i I

The roller and the cam are thus always in intimate contact through the recessed portion 13 of the base-plate, by virtue of a spring-blade 1.4 which is rigidly attached to the block 4 and which acts upon the bearing member 2.

A magnetic armature 15 is attached to the spring-blade 8 at the free extremity of this latter and oppositely facing the permanent magnet 19. The movable contactstud 17 is carried by a light-weight flexible strip 16 which I is in turn attached to the armature 15.

The operation of the apparatus is as follows:

When the detachable unit of FIG. 3 which has been described above :has'been mounted in position in the housing 3 of the block 4 and the stud 6 has been passed through the hole 5, the magnetic armature 15 is normally attracted by the permanent magnet 19 and is applied against abutments, which are not illustrated in the drawings, or even against the polar surface of the magnet. I

As shown in FIG. 1, the roller 11 is applied against the In this position of the armature 15, the contact-studs l8 and 17 come into contact, thus closing the electric circuit. The dimensional characteristics of the diiierent members are such that, in this position, the elastic strip 16 is deformed and, as a result of the rection thereof, makes a contact under pressure between 17 and 18.

By causing the cam 12 to rotate in the direction of the arrow, the shoulder 21 tends to thrust back the roller 11 which, byacting like a push-plate unit, tends to make the strip 9 swing slightly about the articulation 5-6. This movement of the strip tends to deform the springblade 8 which, by bending, producesa pulling effort on I effort of attraction towards the magnet.

ence being made to the accompanying drawings, which are given by way of example only and not in any sense by way of implied limitation, and in which:

FIG. 1 is an elevation in cross-section of a switch in accordance with the invention, in the position of closure of the electric circuit.

FIG. 2 is a view in perspective of a permanent magnet. V I FIG. 3 is an elevationin cross-section of the detachable part.

As the rotation of the cam continues, there comes a moment when the extremity of the strip comes up against the magnetic armature, and by pushing against the said armature compelsthe latter to leave its position of rest. From this moment, the attractive force of the permanent magnet decreases very rapidly and the armature is then practically subjected to nothing more than the elastic force of the spring-blade 8 which tends to revert to its initial shape.

The armature 15 therefore moves away from its position of rest with an acceleration which is not dependent on the rapidity with which the cam is operated.

As a result of the deformation of the elastic strip '16 as explained above, the studs 17 and 18 remain in contact during the first moments of travel of the armature 15. When the said studs separate, said armature 15 has gained great speed and the acceleration imparted to the elastic strip 1'6 and to the light-weight stud 17 is therefore very great.

The breaking of the electric circuit thus takes place in the field of the permanent magnet 20, and in very sud den manner, as set forth in the foregoing description. For these two reasons combined, the duration of the electric breaking-arc is thereby reduced to a substantial extent and, as a consequence thereof, the behaviour and resistance of the contact-studs are also improved.

The closure of the electric circuit is carried out in a natural manner by bringing back the cam 12 into the initial position, namely that of FIG. 1. The strip 9 reverts progressively to its initial position under the effect of the elastic strip M which acts upon the bearing member 2. During this movement of the strip, there comes a moment when the armature 15 is violently drawnto- Wards the magnet 1*9, thereby bringing into contact the studs 17 and 18 and resulting in the complete closure of the electric circuit.

It can be seen in FIG. 1 that, by only slightly unscrewing the stud 6, the articulation 6 is then released and the detachable portion defined by FIG. 3 can then be very rapidly separated from the remainder of the apparatus.

The cleaning or if necessary, the replacement of the contact-studs thus necessitates immobilization only for a very short period of time.

A number of switches as thus described can be placed side by side on a same base-plate; the control cams are in that case mounted on a common shaft and suitably displaced with respect to each other. A change-over switch is thus constituted, without thereby departing from the scope of the present invention.

What I claim is:

1. An electric current switch comprising:

a base;

a first contact mounted on said base;

a second contact and mounting means for said second contact;

said mounting means including an element movably mounted on said base, a magnetic armature and re silient means mounted on said base and connected to said magnetic armature for normally holding said magnetic armature a selected distance from said element but supporting said armature for limited movement with respect to said element, said second contact being supported by said magnetic armature for selective engagement with said first contact;

a permanent magnet mounted on said base close to said magnetic armature for continuously urging same into a selected position with respect to said first contact; and

means acting on said element for moving same with respect to said permanent magnet and said resilient means whereby said magnetic armature will be urged away from said permanent magnet but will be held in said selectedv position by the attraction of said permanent magnet until said element has moved a predetermined distance with respect to said resilient means and said resilient means is thereby stressed to such an extent that it overcomes the attraction of said permanent magnet whereupon said armature will be suddenly moved away from said permanent magnet and said second contact will move with respect to said first contact.

2. An electric current switch according to claim 1, in which a second magnet is mounted on said base adjacent said contacts to create a magnetic field in the vicinity thereof.

3. An electric current switch comprising:

a base;

a first contact mounted on said base;

a second contact and mounting means for said second contact, said mounting means being mounted on said base;

said mounting means comprising a base strip mounted on said base for movement with respect thereto, a spring blade and means mounting said spring blade on said base above said base strip for flexing movement with respect to said base strip, a magnetic armature connected to said spring blade for movement with respect to said base strip, a flexible strip mounted on said magnetic armature, said second contact being mounted on said flexible strip and being engageable with said first contact;

a permanent magnet mounted on said base for continuously urging said magnetic armature into one position with respect to said first contact; and

means acting on said base strip for moving same with respect to said permanent magnet and said magnetic armature whereby said magnetic armature will be urged away from said magnet but will be held in said one position by the attraction of said permanent magnet until said base strip has moved a predetermined distance engages said magnetic armature and said spring blade is stressed to such an extent that it overcomes the attraction of said permanent magnet whereupon said armature will be suddenly moved away from said permanent magnet and said second contact will move with respect to said first contact.

4. An electric current switch according to claim 3 in which said base strip and said spring blade are elongated thin members and are substantially parallel with and spaced from each other, said spring blade being fixed at one end with respect to said base strip and being supported in cantilevered fashion with respect to said base strip.

5. An electric current switch according to claim 4, in which the base strip is disposed between said base and said spring blade and is mounted at one end thereof on said base for movement toward and away from said base, the other end of said base strip being received between said permanent magnet and said magnetic armature, said base strip having a cam follower mounted thereon between the ends thereof;

a rotatable cam engaging said cam follower of effecting movement of said base strip with respect to said base and resilient means urging said base strip toward said cam.

6. An electric current switch, comprising:

a base;

a first contact mounted on said base;

an elongated, thin base strip and means releasably securing said base strip adjacent one end thereof to said base, said base strip otherwise being free from connection to said base so as to be capable of flexing with respect to said base;

an elongated spring strip mounted adjacent one end thereof on said base strip and supported in cantilevered fashion substantially parallel with and spaced from said base strip and being movable toward and away from said base strip;

a permanent magnet mounted on said base adjacent the free end of said spring strip;

a magnetic armature mounted on the free end of said spring strip and opposed to said permanent magnet so that said magnetic armature is continuously urged toward said permanent magnet;

21. flexible strip mounted on the free end of said spring strip and extending lengthwise away therefrom;

a second contact mounted on said flexible strip and adapted for engagement with said first contact; and

cam means engaging said base strip between the ends 5 thereof for flexing said base strip toward and away 2,452,425 from said base thereby moving said second contact 2,480,127 toward and away from said first contact. 2,619,569 References Cited in the file of this patent UNITED STATES PATENTS 5 1,892,008 Ross Dec. 27, 1932 2,402,173 Malone June 18,1946 3 3,

6 Berkholder Oct. 26, 1948 'Frerer, Aug 30, 1949 Savage Nov. 25, 1952 Crouch Aug. 7, 1956 Senn Mar. 5, 1957 FOREIGN PATENTS Switzerland Aug. 31, 1957 

6. AN ELECTRIC CURRENT SWITCH, COMPRISING: A BASE; A FIRST CONTACT MOUNTED ON SAID BASE; AN ELONGATED, THIN BASE STRIP AND MEANS RELEASBLY SECURING SAID BASE STRIP ADJACENT ONE END THEREOF TO SAID BASE, SAID BASE STRIP OTHERWISE BEING FREE FROM CONNECTION TO SAID BASE SO AS TO BE CAPABLE OF FLEXING WITH RESPECT TO SAID BASE; AN ELONGATED SPRING STRIP MOUNTED ADJACENT ONE END THEREOF ON SAID BASE STRIP AND SUPPORTED IN CANTILEVERED FASHION SUBSTANTIALLY PARALLEL WITH AND SPACED FROM SAID BASE STRIP AND BEING MOVABLE TOWARD AND AWAY FROM SAID BASE STRIP; A PERMANENT MAGNET MOUNTED ON SAID BASE ADJACENT THE FREE END OF SAID SPRING STRIP; A MAGNETIC ARMATURE MOUNTED ON THE FREE END OF SAID SPRING STRIP AND OPPOSED TO SAID PERMANENT MAGNET SO THAT SAID MAGNETIC ARMATURE IS CONTINUOUSLY URGED TOWARD SAID PERMANENT MAGNET; A FLEXIBLE STRIP MOUNTED ON THE FREE END OF SAID SPRING STRIP AND EXTENDING LENGTHWISE AWAY THEREFROM; A SECOND CONTACT MOUNTED ON SAID FLEXIBLE STRIP AND ADAPTED FOR ENGAGEMENT WITH SAID FIRST CONTACT; AND CAM MEANS ENGAGING SAID BASE STRIP BETWEEN THE ENDS THEREOF FOR FLEXING SAID BASE STRIP TOWARD AND AWAY FROM SAID BASE THEREBY MOVING SAID SECOND CONTACT TOWARD AND AWAY FROM SAID FIRST CONTACT. 